The present application claims priority under 35 USC 119 to Japanese Patent Application No. 2000-277186 filed on Sep. 12, 2000 the entire contents thereof is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a structure of arranging a fuel injection valve of an engine preferable for improving engine performance regardless of the layout of the engine parts.
2. Description of Background Art
FIG. 4 is a sectional view showing a fuel injection state of a conventional engine and showing a state in which an intake manifold 101 is attached to a cylinder head 100, a fuel injection valve 102 is attached to the intake manifold 101 and fuel 104 is injected from the fuel injection valve 102 into an intake path 103 provided adjacent to the cylinder head 100. An intake side valve seat opening portion 105 of the intake path 103 is provided that leads to a combustion chamber 106. An intake valve 107 is provided for opening and closing the opening portion 105. An exhaust path 108 is provided with an exhaust side valve seat opening portion 111 of the exhaust path 108 leading to the combustion chamber 106. An exhaust valve 112 is provided for opening and closing the opening portion 111.
FIG. 5 is a view taken along the arrow 5 direction in FIG. 4. FIG. 5 illustrates an arrangement of the intake manifold 101 such that the center of an outlet 101a thereof coincides with a center line 113 of the combustion chamber 106. The fuel injection valve 102 of a two-direction injection type is arranged such that an axis line thereof coincides with the center line 113 of the combustion chamber 106. Portions of the fuel 104 are sprayed toward two of the opening portions 105 in line with a cam shaft 114 indicated by an imaginary line.
For example, there is a case in which the intake manifold 101 cannot be arranged to coincide with the center line 113 of the combustion chamber 106 for attaching an ignition plug or other engine parts to the cylinder head 100 or for some other reason, in such a case, the intake manifold 101 is attached to the cylinder head 100 by moving the intake manifold 101 in a direction along the cam shaft 114. In accordance therewith, when the fuel injection valve 102 is also moved in the direction of the arrow in FIG. 5 and the injection ranges of the portions of fuel 104 are changed, an amount of the injected fuel which adheres to inner walls of the opening portions 105, is increased and the fuel becomes difficult to vaporize. Therefore, a mixture in the combustion chamber becomes non-uniform, which has an influence on the output performance of the engine.
Hence, it is an object of the present invention to improve engine performance regardless of the layout of the engine parts by reforming a structure of arranging a fuel injection valve of an engine.
According to the present invention, a structure is provided for arranging a fuel injection valve of an engine characterized in that in an engine a fuel injection valve of a 2-direction injection type is attached to an intake manifold for injecting fuel into a combustion chamber having two intake holes aligned along a cam shaft. An axis line of the fuel injection valve is offset from a center of the combustion chamber by moving the fuel injection valve along the cam shaft to limit an injection range of the fuel injection valve as the fuel contacts with an inner wall of the intake hole.
By offsetting the axis line of the fuel injection valve from the center of the combustion chamber along the cam shaft by constituting the limit by bringing the injection range of the fuel injection valve into contact with the inner wall of the intake hole, even when a position of the intake manifold is obliged to move along the cam shaft, the fuel injected from the fuel injection valve can be made to be difficult to adhere to the inner wall of the intake hole and vaporization of the fuel can be expedited. Therefore, a mixture in the combustion chamber can be made uniform and engine performance such as response performance of engine rotation, fuel consumption, exhaust gas properties, occurrence of knocking or the like when the throttle valve is opened can be improved.
According to the present invention, the engine is a V-type 2-cylinder engine offsetting respective cylinders from each other in a crankshaft direction and arranged with a throttle body for two of the cylinders on one side of the engine in the crankshaft direction, a first fuel injection valve facing a first combustion chamber proximate to the throttle body is offset in a direction of being remote from the throttle body and a second fuel injection valve facing a second combustion chamber remote from the throttle body is offset to a side of the throttle body.
According to the V-type 2-cylinder engine offsetting the respective cylinders from each other in the crankshaft direction and arranging the throttle body for the two cylinders on one side of the engine in the crankshaft direction, respective lengths of the intake manifolds connected to the respective cylinders differ from each other and accordingly, a difference is produced in intake air amounts of the respective combustion chambers, by unbalance in outputs among the cylinders, it is difficult to increase output. However, for example, in the case in which in order to prolong the short intake manifold provided on the side of the first combustion chamber, an outlet of the intake manifold on a side of the intake path is moved in a direction of being remote from the throttle body and in order to shorten the intake manifold on the side of the second combustion chamber longer than the intake manifold on the side of the first combustion chamber, an outlet of the intake manifold on the side of the intake path is moved to the side of the throttle body to thereby reduce a difference in the respective lengths of the intake manifolds, when the first fuel injection valve is offset in the direction of being remote from the throttle body and the second fuel injection valve is offset to the side of the throttle body, while improving engine performance such as response performance of engine rotation, fuel consumption, exhaust gas properties, occurrence of knocking or the like when the throttle valve is opened, an increase in engine output can be achieved by substantially equal length formation of the respective intake manifolds.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.